Support is requested to continue the development of sold-state of NMR spectroscopy as a method for determining the structures of proteins, and to make the instrumentation and methodology for high field solid-state NMR spectroscopy available to the biomedical research community. The mechanism for this is the competitive renewal of P41 RR09793, which supports the Resource for Solid-State NMR of proteins at the University of Pennsylvania. This is an ideal location for a Resource, since the University is located in the Department of Chemistry is located close to the School of Medicine and the Wistar Institute. The technological research and development consists of the design, construction, and optimization of instrumentation for high-field sold-state NMR spectroscopy and the development of new experimental methods for sold- state NMR spectroscopy; the development of solid-state NMR spectroscopy as a general method for determining the structures of membrane proteins in lipid bilayers; and the application of solid-state NMR spectroscopy to the determination of the structures of peptides displayed on the surface of filamentous bacteriophages. The Core Application project is the structure determination of merF and merT proteins of the bacterial mercury Vpu, ion-channel proteins, colicin myristoylated recoverin, myristoylated protein G, farnesylated Ras, magainin, and many other membrane associated peptides and proteins. Training will occur through formal research, the participation of undergraduate, graduate, and postdoctoral students in the research, the participation of visiting scientists in their own projects, and workshops. Dissemination will occur through publications, the web page, workshops, and symposia.